TeleGeography: Ethernet VPLS, EoDWDM interest grows, while IP/VPN expansion dips
HISTORICAL SPACE FREQUENCIES. The first satellite to orbit the Earth was Sputnik 1, launched by the Soviets in October 1957. It carried two radio beacons on frequencies of 20.005 and 40.01 MHz. The Soviets continued to use frequencies around 20 MHz and even some around 15 MHz for many subsequent missions. This tends to be used for uplinks of the satellites that downlink in the 137 - 138 MHz band. 2  149.95 - 150.05 MHz. 3  This is used by satellites providing positioning, time and frequency services, by ionospheric research and other satellites.
A satellite in low orbit typically about 800 km from the Earth is exposed to an immense gravitational pull and has to move at considerable speed in order to generate a corresponding centrifugal force. There is a direct connection between the distance from the Earth and the orbital velocity of the satellite. At a distance of 36,000 km, the orbiting time is 24 hours, corresponding to the Earth's rotation time. At this distance, a satellite above the Equator will be stationary in relation to the Earth.